It is known to use polysaccharide gums having β1-4 linkage (hereinafter referred to as β-1,4-polysaccharides) as ingredients in detergent compositions, e.g. guar gum when used as a thickener in bleach compositions and liquid fabric washing compositions, and as additives to detergent powders e.g. to improve the structural and/or free-flowing properties of the powders.
It is also known to use various different materials in laundry products for color care, e.g. to reduce the fading of coloured dyes in the fabric due to repeated washes.
It is has now been found by the applicants that surprisingly, β1-4 polysaccharides also are useful in detergent products for fabric care benefits such as colour care performance, as well as anti-pilling. Unfortunately, at levels required for this purpose, the applicants have noticed a negative in terms of enhanced staining with particulate stains on the fabric.
This problem has now been overcome by modifying the naturally occurring polysaccharides that their weight average molar weight is 250,000 or less.
Techniques for reducing the molecular weight of naturally occurring polysaccharides are well known in the art.
Degradation of galactomannans, polyuronic acids and galactans by a thermal process in an oxygen-free atmosphere is described in GB-A-1 042 438.
Galactomannans for anti-gelling of food products, by peroxide or acid hydrolysis is disclosed in GB-A-1 565 006.
GB-A-834 375 describes a method for retarding the degradation of galactomannans in hot aqueous systems by inclusion of certain water-soluble metal salts.
According to U.S. Pat. No. 2,553,485, manno-galactans can be heat degraded to modify their adhesive properties.
The acid hydrolysis of partially hydrated carbohydrate gums at elevated temperatures is the subject of WO 93/15116.
Proteolytic degradation of tamarind seed kernel polysaccharide is described in U.S. Pat. No. 3,480,511 and Ind. J. Technology, Vol. 8, September 1970, H. C. Srivastava et al, pp 347-349.
Another non-laundry use of low molecular polysaccharide is disclosed in GB-A-2 314 840. According to this teaching, polysaccharides having a molecular weight of between 1,000 and 50,000 are useful for wound dressings oR peptide/protein binding.
As far as use of low molecular polysaccharides in surfactant-based products is concerned, EP-A-367 335 discloses use of a cationic guargum having a molecular weight of 50,000-100,000,000 preferably 100,000-500,000, especially 250,000-400.000 to improve the feel of toilet bars based on alkali metal soaps. According to EP-A-227 321, the mildness of soap bars is improved using a hydrated cationic polymeric polysaccharide having from 5-6 saccharide units on average. Another soap bar containing a cationic polysaccharide having a molecular weight of 1,000-3,000,000, preferably 2,500-350,000 is disclosed in U.S. Pat. No. 5,064,555.
U.S. Pat. No. 4,179,382 discloses a textile softening agent which includes a cationic salt which optionally may be a cationic polysaccharide, e.g. having a molecular weight of 220,000.
However, none of the aforementioned reference discloses a modified low molecular weight naturally occurring polysaccharide as useful for conferring care benefits in fabric treatment products, e.g. for use in the wash and/or rinse.
Research Disclosure 172011 discloses the use of modified gum. JP-A-51020203 discloses the use of a gum modified by the addition of hydroxy-alkyl ether groups. These are both anti-redeposition agents intended to hold soil in solution and prevent it being re-deposited onto fabric.
US-A4661267 discloses a cationic modified material as does DE-A-2925869, GB-A-2039556, DE-A-3531756 and U.S. Pat. No. 4,179,382. These are substantive materials and all appear to have some kind of softening benefit.
WO-A-9109106 relates to a toilet bar for skin cleaning. This illustrates that short chain guar gums am known to exist, but says nothing about their potential for use in the manner specified in the present claims.
DK 9801395 discloses a method of ‘biopolishng’ fabric that gives a protective effect against fibre damage if used in a finishing process. The polymers are said to have an anti-reduction effect if used in a laundering process. For the finishing effect materials are used in an undisguised form and treated with enzyme only after application to the cloth.